Another Reason To Eat Your Vegetables

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Have you ever heard of age-related macular degeneration? Probably not, unless you, a relative, or a friend have it. Macular degeneration affects more than 10 million Americans and is the leading cause of irreversible blindness among persons older than 65 years. Currently, there is no effective treatment for macular degeneration, and little information is available on its prevention. An exciting recent study suggests that eating dark green leafy vegetables like spinach, collard greens, and kale could reduce risk of macular degeneration.

Joanne Seddon, M.D., and co-investigators examined more than 350 older adults with macular degeneration. Their diets were compared with those of 520 adults without macular degeneration. The most promising results were those related to the carotenoids. (Carotenoids are substances like beta-carotene which are found in foods.) Those subjects with the highest intakes of dietary carotenoids had a 43% lower risk for macular degeneration compared with those with the lowest intakes of carotenoids. When specific carotenoids were examined, two carotenoids, lutein and zeaxanthin, were most strongly associated with reduced risk of macular degeneration. Until recently, it was not possible separately to analyze lutein and zeaxanthin; so they are usually listed together in food composition tables.

Dark green leafy vegetables are especially good sources of lutein. Subjects with the lowest risk of developing macular degeneration ate an average of 5757 micrograms of lutein/zeaxanthin daily. This is the equivalent of about 1/4 cup or less of cooked kale, collard greens, or spinach. Table 1 provides amounts of lutein/zeaxanthin in commonly eaten foods and can be used to assess your intake of these carotenoids. The investigators examined specific foods and found that eating spinach or collard greens (1/2 cup 5 or more times per week) was associated with an 86% lower risk for macular degeneration compared with eating those greens less than once a month.

Use of vitamin supplements (vitamin A, vitamin C, or vitamin E) was not associated with reduced risk of macular degeneration. The authors recommend increasing the consumption of dark green, leafy vegetables to reduce risk of developing macular degeneration.